EN
The study presents the geomorphological effects of extreme hydroclimatic phenomena such as violent downpours, widespread rainfalls with a high sum of precipitation, and intensive snowmelt occurring in the eastern part of Polish Uplands between the Vistula and the Bug rivers. The intensity and impact of these phenomena on relief is exceptionally varied here due to the variety of natural conditions as well as the degree and type of land use. These conditions result in the various kinds, formation time and volume of surface runoff as well as the intensity and volume of erosion. The impact of extreme geomorphological processes is particularly pronounced in the case of agriculturally used loess-covered areas with strong relief that cover approx. 30% of the area. In morphological terms, the most effective are the processes of rill erosion in slopewash systems as well as gully erosion processes with the predominance of piping. These processes, along with tillage erosion, determine the development trends of contemporary slope relief in this part of the uplands. In slopewash systems, rainwater runoff causes the movement of material from slopes to valley bottoms that are dissected as a result of snowmelt runoff. In erosion systems (gully systems) during snowmelt, the edges of gullies are dissected (mainly through piping) and their bottoms are covered by sediments that, in turn, are dissected by rainwater runoff. In the valleys of rivers of a low hydrological order, extreme channel processes occur during torrential summer downpours. The bottoms of large valleys are intensively shaped primarily during high water stages caused by snowmelt and rainfall.